Textbook in PDF format The book fills the existing gap in the literature on clean and hydrogen combustion technologies for industrial applications. This gas is created due to the absence of a comprehensive textbook that covers such kinds of developments. This book can be used as a textbook for graduate-level courses in the areas of clean and hydrogen combustion and as a reference book for short courses to be offered to mechanical and aerospace engineers and young researchers worldwide. The book chapters consider investigating clean and hydrogen combustion techniques for different applications based on experimental measurements along with detailed numerical simulations. Detailed descriptions of the different numerical models are presented for given applications to solve for the flow/flame fields, which are very important, especially for beginners and undergraduate students in the fields of clean and hydrogen combustion. Preface. Introduction. Engines, Fuels, and Thermodynamics of Combustion. Fuel/Oxidizer-Flexible Lean Premixed Combustion. Stratified and Hydrogen Combustion for Higher Turndown and Lower Emissions. Application of Lean Premixed Combustion for Emission Control in Different Combustors. Applications of Fuel/Oxidizer-Flexible Premixed Combustion in Gas Turbines. Energy and Hydrogen Production in Novel Membrane Reactors